Various hand held or portable lighting devices, including flashlights, are known in the art. Flashlights typically include one or more dry cell batteries having positive and negative electrodes. In certain flashlights, the batteries are arranged in series in a battery compartment of the flashlight barrel or housing.
An electrical circuit is frequently formed between the batteries and light source, such as a lamp bulb, as follows. A battery electrode through conductive means is electrically coupled to an electrode of a lamp bulb. After passing through the lamp bulb, the electrical circuit continues through a second electrode of the lamp bulb which is in electrical contact with a conductive means that is in turn in electrical contact with the other electrode of the battery. Typically, the circuit includes a switch to open or close the circuit. Actuation of the switch to close the electrical circuit enables current to pass through the lamp bulb thereby generating light.
Rechargeable flashlights may include recharging rings that are located on the exterior of the flashlight and that are electrically coupled to the rechargeable batteries therein. To recharge the batteries in such flashlights, the flashlight may be placed in a recharging cradle so that the exterior recharging rings are electrically coupled to the cradle.
Some manufacturers arrange the rechargeable batteries in series within a plastic wrap to form a battery pack that is installed within the flashlight. Nickel-cadmium (NiCd) batteries have been used in such rechargeable battery packs. However, NiCd batteries have been banned from use in certain countries due to their impact on the environment. Indeed, NiCd batteries can no longer be sold in Europe, and this prohibition will soon exist in the United States.
Accordingly, an alternate to the NiCd battery is required for future flashlights. And in order to continue using flashlights originally equipped with NiCd battery packs, a replacement battery pack with other types of batteries or battery chemistry is needed.
The nickel-metal hydride (NiMH) battery and the lithium-ion battery (Li-Ion) are both suitable replacements in that they do not create the same environmental issues as do NiCd battery packs. Furthermore, the NiMH battery provides increased capacity over a similarly sized NiCd battery, while the Li-Ion battery provides a higher volumetric energy density than that of a NiCd battery. However, issues may arise regarding the compatibility of these alternate battery packs with charging cradles or other devices originally designed to charge NiCd battery packs.
Certain NiCd battery packs may include five 2.2 Ah NiCd cells connected in series. The nominal voltage of this battery pack is 6.0V. The charger for such a battery pack may use a constant current charging scheme with a charging rate set to C/10, where C is the capacity of the batteries. Since the capacity of this battery pack is 2.2 Ah, the flashlight is configured to charge at 0.220 Amps (or 220 mA). This C/10 scheme is known as “standard charge” and generally takes fifteen hours to charge a fully depleted NiCd battery pack. After fifteen hours, the charger may be switched from this “standard charge” C/10 scheme to a C/20 charge rate for an indefinite period of time (until the flashlight is removed). The C/20 scheme is also known as a trickle charge rate. However, the switch from the C/10 scheme to the C/20 scheme is not required with NiCd batteries and the circuit design is simplified if the charge rate is kept at C/10.
When NiMH batteries are being charged, however, charging at C/10 will over charge the NiMH batteries after about 15 hours of charge. Accordingly, a trickle charge and the associated circuitry are necessary to replenish the self discharge of NiMH batteries.
A flashlight that may perform multiple functions beyond providing a steady stream of light has also become desirable. Indeed, the functions performed by a flashlight, such as an SOS blinking function, may sometimes become a life-saving means. However, any functions performed by the flashlight are typically built in to the flashlight at the time it is manufactured, and are not added by a user later on. Accordingly, if a user desires a flashlight having multiple functions, the user must buy the flashlight with such functions already built in. As a result, users may discard existing flashlights that do not perform multiple functions and buy new flashlights that do perform such functions. However, where such discarded flashlights contain NiCd battery packs, environmental issues arise.
In view of the foregoing, a need exists for a rechargeable battery pack that does not create the same environmental issues like NiCd batteries. A need also exists for such a battery pack to use a charging scheme that is compatible with a previously existing flashlight into which it is installed. A need also exists for such a battery pack to provide multiple functions when installed into a previously existing flashlight incapable of providing such functions. A need also exists for an improved apparatus to hold batteries in a battery pack.